This invention is generally directed to organic glasses, and layered photoresponsive imaging members thereof. More specifically, the present invention in an embodiment thereof relates to mixtures comprised of polymers and small molecules, such as charge transporting, especially hole transporting molecules, like aryl diamines, and photoconductive members thereof, wherein the mixture functions in embodiments as an exceptional hole transporting medium in that, for example, ultra high hole mobilities are achieved with these mixtures, especially a mixture of a biphenyl diamine compound, such as N,N'-bis(4-methylphenyl)-N,N'-bis(4-ethylphenyl)-[1,1'-(3,3'-dimethyl)biph enyl]-4,4'-diamine (ETPD) and a polysilylene, such as, for example, from about 1.times.10.sup.-1 to about 10.sup.-1 cm.sup.2 /volts per second at room temperature, about 25.degree. C. In one embodiment of the present invention, there are provided organic photoconductive layered imaging members comprised of photogenerating layers and charge, especially hole transport layers comprises of organic glasses, and more specifically a mixture comprised of polysilylenes and certain aryl amines dopants as illustrated herein, and more specifically in U.S. Pat. No. 4,833,054, the disclosure of which is totally incorporated herein by reference. In one embodiment of the present invention, there is provided a photoresponsive imaging member or device comprised of a supporting substrate, a photogenerating layer comprised of photogenerating pigments optionally dispersed in a resin binder, and a hole transport layer comprised of a mixture of a polysilylene, reference U.S. Pat. No. 4,618,551, the disclosure of which is totally incorporated herein by reference, and a biphenyl diamine compound, such as N,N'-bis(4-methylphenyl)-N,N'-bis(4-ethylphenyl)-[1,1'-(3,3'-dimethyl)biph enyl]-4,4'-diamine (ETPD). The photoresponsive imaging members of the present invention can be selected for various electrophotographic imaging and printing processes, especially xerographic processes wherein, for example, latent images are formed thereon, followed by development and transfer to a suitable substrate. Furthermore, the charge transporting mixtures of the present invention can, it is believed, be selected for electroluminescent display panels, field effect transistors, wherein, for example, there are usually needed hole drift mobilities of from about 10.sup.-2 to about 10.sup.-1 cm.sup.2 /volts per second; organic electronic devices, photoelectric devices, such as photocells where high hole mobilities are usually desired, and the like. The present invention in an embodiment is also directed to processes for improving the hole mobilities of various components by the addition thereto of certain aryl amines.
The selection of polysilylenes as hole transport molecules for utilization in layered photoconductive imaging members is known, reference U.S. Pat. No. 4,618,551, the disclosure of which is totally incorporated herein by reference. In column 6 of this patent, it is indicated that there can be selected as the hole transporting compound a number of polysilylenes, about 40 weight percent of a dispersed aryl amine, and about 60 percent of poly(phenyl methylsilylene). With the charge transporting mixtures of the present invention, there is enabled an increase in hole mobility of about a factor of 20 times as compared to the aforementioned 40 to 60 mixture. Also, imaging members with aryl amine hole transport and photogenerting layers are known, reference for example U.S. Pat. No. 4,265,990. Organic glasses exhibiting low charge mobilities, that is for example wherein the hole mobility is about 10.sup.-3 cm.sup.2 /volts per second at room temperature and electric fields of about 10.sup.5 volts/centimeter are known, reference H. Jen Yuh and D. M. Pai, paper presented at the Fourth International Conference on Unconventional Photoactive Solids, San Jose Calif., Oct. 16 to Oct. 18, 1989. In the aforementioned paper, there is illustrated that hole mobilities in excess of 10.sup.-3 cm.sup.2 /volts per second are achieved in a homogeneous glass with about 75 weight percent of N,N'-bis(4-methylphenyl)-N,N'-bis(4-ethylphenyl)-[1,1'-(3,3'-dimethyl)biph enyl]-4,4'-diamine (ETPD) and about 25 weight percent of polystyrene. In the Journal of Chemical Society, received Jan. 31, 1990, page 805, there is illustrated enhanced hole drift mobility in organopolysilanes doped with certain low molecular weight charge transport compounds. With the invention of the present application, in embodiments thereof the hole mobilities are substantially higher than those as illustrated in the aforementioned article, for example up to 100 times higher in a number of embodiments.
In a patentability search report there were listed the following U.S. patents: U.S. Pat. No. 4,618,551, mentioned herein; U.S. Pat. No. 4,772,525, which discloses in columns 6 and 7 about 90 percent of poly(phenylmethyl silylene) with about 10 percent by weight of a dispersed aryl amine; U.S. Pat. Nos. 4,758,488; 4,744,159 and 4,855,201 which disclose polysilylene charge transport layers; and as collateral interest according to the searcher U.S. Pat. Nos. 4,356,246 and 4,544,729. The disclosures of each of the aforementioned patents are totally incorporated herein by reference.
Illustrated in U.S. Pat. No. 4,315,981 are organic double layered electrophotographic recording materials consisting of an electroconductive support with a photoconductive double layer of organic materials, which consist of a homogeneous opaque charge carrier producing dyestuff layer obtained from an annealed quinone, or the substitution product thereof selected from the group consisting of dibenzoperylene, quinone, anthraquinone, pyranthrone, dibenzathrone, and flaventhrone, and a transparent top layer of insulating materials of at least one charge transporting compound, which transport layer consists of a charge transporting monomer, reference for example column 2, lines 37 to 56. Further, as indicated in column 4, lines 1 to 22, as the Formula 9 compound for the imaging member of the '981 patent there can be selected dibromo-8,16-pyranthrenedione (Indanthrene Orange RRTS, C.I. 59,705). Moreover, it is indicated in column 4, beginning at around line 53, that the organic dyestuff layer may be applied by vapor depositing the dyestuff in a vacuum. Also, this patent discloses a number of resinous binders for the charge transport layer including polycarbonate resins, reference column 7. Further, in U.S. Pat. No. 3,871,882 there are disclosed layered electrophotographic recording materials containing an electroconductive support material and a photoconductive double layer of organic materials, reference for example the Abstract of the Disclosure. Other representative patents of background interest include U.S. Pat. No. 3,871,882 and 3,973,959.
In Konishiroku Kokai Japanese 59/184349/A2[84/184349], Oct. 19, 1984, there is disclosed the use of selected pyranthrones as charge generator layers in conjunction with hydrazone charge transport layers. Specifically, a solution coated dispersion of dibromo-8,16-pyranthrenedione in a polymer binder can be selected as the charge generator layer. Also, in U.S. Pat. No. 3,877,935 there are disclosed imaging members with dibromo-8,16-pyranthrenedione vacuum coated charge generator layers contiguous with poly(vinyl carbazole) charge transport layers.
As a result of a patentability search in a copending application, there were selected U.S. Pat. Nos. 4,028,102; 4,399,207; 4,454,211; 4,554,231 and 4,714,666. In the '102 patent, there are illustrated diamine condensation products in double layered photoconductive recording elements. More specifically, there are disclosed in the '102 patent condensation products of o-phenylamine diamine or 1,8-diaminylnaphthyline and 4,10-benzothioxanthrene-3,1'-dicarboxylic anhydride of the formulas as illustrated in column 2, and of the formulas 1 to 5, reference column 3, beginning at line 55. The '207 patent discloses electrophotographic photosensitive members with hydrazone compounds of the formula, for example, as illustrated in the Abstract of the Disclosure and in column 2. Examples of charge generating layer materials are illustrated beginning in column 16, line 65, and include, for example, phthalocyanine pigments, perylene pigments, and the like, typical examples of which are specifically recited in columns 17 through 26. The '211 patent discloses electrophotographic photosensitive members with pyrazoline charge transport materials, see for example column 2, beginning at line 35. Specific organic photoconductive materials or charge transporting materials for use in the invention of the '211 patent are illustrated according to the teachings thereof in columns 3 and 4, formulas 1 and 2, of the '211 patent. Charge generating layers for the photoconductive members in the '211 patent are illustrated in column 42, beginning at line 11, and include, for example, organic substances such as pyrylium dyes, thioperylium dyes, perylene pigments, and the like with specific examples of charge generating materials being illustrated in columns 42 to 52. Also, it is disclosed in column 57 that a charge generating layer can be formed on aluminum plate by the vacuum deposition of a perylene pigment having carbon atom bridges at the 1, 12 and 6, 7 positions of the common perylene molecule. In U.S. Pat. No. 4,554,231, there is illustrated an electrophotosensitive member comprised of a layer containing hydrazone compound of the formula, for example, as illustrated in the Abstract of the Disclosure, which hydrazone compound is selected as charge transport material, reference column 5, line 30, and wherein there are selected various charge generating layer materials including, for example, perylium dyes, thiopyrylium dyes, perylene pigments and the like, see column 6, beginning at line 23, and note particularly columns 7 through 12. The use of Vylon 200 on a charge generating layer is disclosed at column 19, lines 15 to 21, and according to the searcher, there is shown at the bottom of column 12 a perylene molecule which may be used, which includes a two carbon atom bridge at both the 1, 12 and 6, 7 positions of a perylene molecule.
Moreover, in U.S. Pat. No. 4,587,189, the disclosure of which is totally incorporated herein by reference, there are illustrated layered imaging members with photoconductive layers comprised of cis and transbis(benzimidazo)perylene pigments and aryl amine charge transport layers.
Additionally, numerous different xerographic photoconductive members are known including, for example, a homogeneous layer of a single material such as vitreous selenium, or a composite layered device containing a dispersion of a photoconductive composition. An example of one type of composite xerographic photoconductive member is described, for example, in U.S. Pat. No. 3,121,006 wherein there are disclosed finely divided particles of a photoconductive inorganic compound dispersed in an electrically insulating organic resin binder.
There are also known photoreceptor materials comprised of inorganic or organic materials wherein the charge carrier generating, and charge carrier transport functions are accomplished by discrete contiguous layers. Additionally, layered photoreceptor materials are disclosed in the prior art which include an overcoating layer of an electrically insulating polymeric material. However, the art of xerography continues to advance and more stringent demands need to be met by the copying apparatus in order to increase performance standards, and to obtain quality images. Also, there have been disclosed other layered photoresponsive devices including those comprised of separate generating layers, and transport layers as described in U.S. Pat. No. 4,265,990, the disclosure of which is totally incorporated herein by reference. Examples of photogenerating layers disclosed in this patent include trigonal selenium and phthalocyanines, while examples of transport layers include certain diamines as mentioned herein.
Many other patents are in existence describing photoresponsive devices including layered devices containing generating substances, such as U.S. Pat. No. 3,041,167 which discloses an overcoated imaging member containing a conductive substrate, a photoconductive layer, and an overcoating layer of an electrically insulating polymeric material. This member is utilized in an electrophotographic copying system by, for example, initially charging the member with an electrostatic charge of a first polarity, and imagewise exposing to form an electrostatic latent image, which can be subsequently developed to form a visible image.
Furthermore, there are disclosed in U.S. Pat. Nos. 4,232,102 and 4,233,383 photoresponsive imaging members comprised of trigonal selenium doped with sodium carbonate, sodium selenite, and trigonal selenium doped with barium carbonate, and barium selenite, or mixtures thereof. Moreover, there are disclosed in U.S. Pat. No. 3,824,099 certain photosensitive hydroxy squaraine compositions. According to the disclosure of this patent, the squaraine compositions are photosensitive in normal electrostatographic imaging systems.
In U.S. Pat. No. 4,508,803, the disclosure of which is totally incorporated herein by reference, there is described an improved photoresponsive device comprised of a supporting substrate, a hole blocking layer, an optional adhesive interface layer, an inorganic photogenerating layer, a photoconducting composition layer comprised of benzyl fluorinated squaraine compositions, and an aryl amine hole transport layer. Other representative patents disclosing photoconductive devices with photogenerating squaraine and aryl amine charge transport components therein include U.S. Pat. Nos. 4,507,408; 4,552,822; 4,559,286; 4,507,480; 4,524,220; 4,524,219; 4,524,218; 4,525,592; 4,559,286; 4,415,639; 4,471,041 and 4,486,520. The disclosures of each of the aforementioned patents are totally incorporated herein by reference.